Cryo Breach

Lorcan Fyfe is a night-shift maintenance technician at an exclusive, subterranean cryonics suspension facility. His routine job consists of monitoring liquid nitrogen levels in massive stainless-steel tanks holding the legally dead bodies of wealthy clients awaiting future medical resurrection. The terror unleashes when the diagnostic panel for Tank #12 alerts him that its internal temperature is rapidly rising.
The frozen corpse inside is generating massive metabolic heat: the client didn't die of a terminal illness, but was frozen to halt an illegal, self-replicating nanotech injection that has begun violently mutating his cellular structure. When the intense heat blows the pressurized steel door open, the entity emerges. It is no longer human, but a grotesque, biomechanical hybrid of tissue and jagged metallic structures that immediately hunts Lorcan for fresh biological carbon.
The facility's AI detects the anomaly and seals the titanium doors in a "Total Quarantine Lockdown, " trapping Lorcan underground. With no way to physically damage the bulletproof entity, Lorcan executes a desperate maneuver. He lures the creature into the central coolant reservoir room and manually destroys the main pressure valves. As hundreds of gallons of raw, -196°C liquid nitrogen explosively flood the room, Lorcan dives into an empty glass-and-steel cryogenic pod, sealing the hatch.
The immense thermal wave hits the creature, flash-freezing it solid mid-lunge. Lorcan survives the monster, but is now trapped inside his own rapidly chilling, pitch-black pod. With his breath crystallizing in the air, he must stare through the frosted glass at the jagged monstrosity paralyzed mere inches from his face, praying the morning shift rescues him before the ice claims him forever.